Problems with Twenex that ought to be fixed  -*-Text-*-

* GTJFN filename defaulting and completion

  Filename defaulting and completion in GTJFN don't work together
properly.  The way that would be right for EMACS is this (assuming
that the defaults are FOO.BAR):

 If the user types UGH⎇ then complete based on what files exist
 starting with UGH, ignoring the defaults.

 If the user types UGH.BLETCH, then use it, regardless of whether the
 file UGH.BLETCH exists.

 If the user types no filenames (<cr> or just a directory name),
 use FOO.BAR as the filenames.

This behavior cannot be obtained by any single setting of the
arguments and flags for GTJFN.  A new flag should be created to make
it possible.

I'm not sure whether UGH<cr> should mean UGH.BAR or UGH.  Probably
UGH.BAR is best, since that traditional interpretation already exists.


* Logical Device Names

  Right now, logical device names don't work because GTJFN only
searches all the directories in the list if an existing file is
required.  For EMACS, the correct behavior would be to find an
existing file on any of the directories but allow a new file to be
created.  Thus, we have the choice of one bug (logical names don't
work) or another bug (files can't be created by visiting them).


* Interrupt characters

  It causes trouble for EMACS that ↑G is not available in the input
stream via PBIN because it causes an interrupt.  Great kludgery is
required to prevent this from losing.  In fact, there are legitimate
TECO programs that would fail to work.  It just happens that EMACS
doesn't contain one of them.  It should be possible for the program to
request that this be done.


* Expunging one file

  It would be useful if EMACS could ask to expunge a specific file.
Then it could expunge excess auto-save files when they are deleted.
The intention of auto saves is that the last several are kept and
others are deleted TO SAVE DISK SPACE.  This is now impossible.


* System-wide Help character

  Wouldn't it be nice if you could type ↑← to get help at any time,
not just inside EMACS?  Twenex already has the ability to give help if
you type "?".  It could give the same help for ↑←.  However, that
might be allowed at some times when "?" might be a useful character
and so cannot be used to ask for help.


* Multiple forks

   When we use EMACS on ITS at MIT, we keep the same EMACS job around
while running other programs, switching back and forth between them.
You can't do this on your system.  You will have to use the command
Push to EXEC to run your other programs underneath the EMACS.  To get
back to the EMACS, do a POP.  This will not kill the EXEC or the other
program you were running under it, and the next time you do a Push to
EXEC you will get back to them.

  However, it is a kludge for the EMACS and the other program not to
be on the same footing; and you can only have one of them.  Really,
EXEC ought to let you create and manipulate multiple forks.

  Then, it would become useful for there to be a way for a program to
return to its superior while providing a string of commands for the
superior to execute.  EMACS could use this to return to EXEC with a
command to run some other program, for instance.